Organic superconductor modified NH2-UiO-66 for boosting photocatalytic Cr(vi) elimination under low-power ultraviolet light

Abstract

NH₂-UiO-66@TCNQ composites (NUxTCy) were fabricated from NH₂-UiO-66 and organic superconductor 7,7,8,8-tetracyanoquinodimethane (TCNQ) by a green ball-milling method. The as-prepared optimum NU90TC10 demonstrated 100% photocatalytic Cr(VI) reduction at an initial concentration of 5 mg L⁻¹ within 50 min under low-power ultraviolet (UV) light. All experiments confirmed that the introduction of low dosage TCNQ into NH₂-UiO-66 could promote Cr(VI) elimination. The results of electron spin resonance (ESR) tests, photochemical Pt⁰ deposition and electrochemical experiments confirmed that the TCNQ superconductor could improve the photocatalytic Cr(VI) removal by accelerating the separation of charge carriers over NH₂-UiO-66. The factors influencing the photocatalytic Cr(VI) elimination over NU90TC10, like pH, hole scavengers and foreign ions, were investigated. The NU90TC10 composite demonstrated excellent stability and practicability up to five cycles. This work provided a new photocatalyst candidate for boosted photocatalytic Cr(VI) elimination under low power LED light.